Timer mechanism



Feb- 19, 1953 D. w. LAVIANA ETAL 3,077,784

TIMER MECHANISM Filed Feb. 19. 1960 3 Sheets-Sheet 2 zy. w f? Feb. 19,1963 D. W. LAvlANA ETAL 3,077,784

TIMER MECHANISM Filed Feb. 19, 1960 5 Sheets-Sheet 5 INVENToRs @02m/aZd. lav/'ana BY Ra 01): D. Z/nefom THE/R ATTORNEY iilite htates arent3,077,784 Patented Feb. 19, 1963 M1784 Elli/IER MECHANESM Donald W.Laviana, Pittsford, and Ralph D. Unterborn,

Rochester, N.Y., assignors to General Motors Corporation, Detroit,Mich., a corporation of Delaware Filed Feb. 19, 1960, Ser. No. 9,837 7Claims. (Cl. 74-3.52)

This invention pertains to timing devices for initiating and controllinga predetermined sequence of operations, and particularly to an improvedtiming mechanism designed for washing machines.

At the present time automatic washing machines are designed to launderclothing composed of both natural and synthetic fabrics. Moreover,clothing manufacturers recommended that synthetic fabrics should not besubjected to the same laundering operations as natural fabrics, and forthis reason washing machines are designed to have both normal and fastcycles of operation. The present invention relates to an improvedimpulse timer of the twospeed type having a constant fill period.Accordingly, among our objects are the provision of a two-speed impulsetimer having a variable ratio drive train; the further provision of atwo-speed impulse timer having a variable ratio gear drive trainincluding interlocking means precluding speed changes under someconditions; the further provision of a two-speed impulse timer having aconstant fill period; and the still further provision of an impulsetimer having ay pair of coaxial fill cams and a pair of spaced coaxialratchet members.

The aforementioned and other objects are accomplished in the presentinvention by utilizing a two-speed gear drive between the motor and thedrive pawl mechanism, and driving the two ratchet members through adouble width pawl. Specifically, the disclosed timer is constructed withtermina-1 block assemblies in accordance with copending applicationSerial No. 786,986 filed I anuary 15, 1959, in the name of Donald W.Laviana including switches of the type disclosed in copendingapplication Serial No. 786,953 tiled January 15, 1959, in the name ofDonald W. Laviana. Thus, the switches are supported on terminal blocks,at least two of which are located in planes normal to each other, theterminal blocks being held in assembled relation with the front and backplates by a plurality of tie bolts. A plurality of rotatable cams isattached to a shaft journalled in the front and back plates forsequentially actuating the several switches.

The timer is driven by a synchronous motor having a drive pinion whichcan be meshed with either of two driven gears supported on a bellcrank.When one of the gears engages the drive pinion, the timer operates on asixty minute cycle, and when the other gear engages the drive pinion,the timer operates on a forty minute cycle.

The gear train rotates a cam for actuating the drive paw] mechanism, andin order to present shifting of the gears when the follower is on thesteep, or drop side of the cam, an interlock is provided.

The drive cam actuates a pawl engageable with a ratchet wheel forrotating the cams in a step by step movement. A second segment ratchetis coaxially mounted on the motor cam for rotation relative thereto, theratchet segment having a constant fill cam portion. The ratchet segmenthas a lost motion connection with the motor cam and is normally springbiased for movement therewith. The arrangement of the constant fillportion cam and the motor cam is such that a constant till period Willbe assured at all times irrespective of the washing interval. Theinterval is four minutes on low speed and two and two-thirds minutes onhigh speed.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred embodiment of the present invention isclearly shown.

ln t-he drawings:

FIGURE l is a plan view of a washing machine timer constructed accordingto the present invention.

FIGURE 2 is an enlarged fragmentary View, partly in elevation and partlyin section, taken along lines 2-2 of FIGURE 1 showing the gear train inone drive position.

FlGURE 3 is an enlarged fragmentary View, partly in section and partlyin elevation similar to FIGURE 2 showing the gear train in the otherdrive position.

FIGURE 4 is an exploded isometric View of the improved timer assembly.

With particular reference to FIGURE 1, the timer is is driven by asynchronous motor indicated by numeral 10, the housing of which isattached by screws 12 to a backplate 14. The back plate has a dishedcover 16 attached thereto which forms a chamber with the back plate 14for enclosing the gear train and drive pawl mechanism, to be described.A plurality of terminal blocks 18, at least two of which are arranged inplanes normal to each other, are held in assembled relation with theback plate i4 and a front plate 20 by tie bolts 22. The terminal blocks13 support terminals as indicated by numeral '24, and a shaft 25 capableof both rotation and limited axial movement is journalled in the frontand rear plates 14 and Ztl.

With reference to FGURES 2 and 4, the synchronous motor lt), whenenergized, drives a pinion gear 26 attached to a motor output shaft 2Ssupported for rotation in the back plate 14. rfhe drive pinion 26 hastwelve teeth. In the position shown FIGURE 2, the drive pinion 26 mesheswith an eighteen tooth gear 30 rotatably supported on a stub shaft 32carried by a bellcrank, or keeper plate, 3S. The keeper plate alsokcarries a fifteen tooth gear 63 journalled on shaft 7i). The gear 30 isintegral with a twelve tooth gear 36, which, in FIGURES 2, 3 and 4,meshes with a thirty-two tooth gear 3S rotatably supported on a pivotstud 4@ journalled in the back plate 14. Plate 35 is rigidly connectedwith shift plate 34 allowing plates 34 and 35 to pivot about stud 40.The thirty-two tooth gear 3g is integral with a ifteen tooth gear 42that meshes with a seventy-five tooth gear 44 attached to a shaft 46.The shaft 46 is journalled in the rear plate 14. With this drive train,the gear 44 will rotate one revolution for every twenty revolutions ofthe pinion 26, since the gea-r 44 will rotate thirty revolutions perhour for a sixty minute wash cycle, the pinion gear 26 is driven by themotor at ten revolutions per minute.

With reference to FIGURES 3 and 4, when the shift plate 34 is moved inthe clockwise direction, the drive pinion 26 engages the fteen toothgear 68. The gear 68 drives the gear 38 which rotates the gear 42 havingengagement with the gear 44. Since the drive pinion 26 rotates at tenrevolutions per minute, the gear 44 will be driven at forty-fiverevolutions per hour so that the sixty toothed rachet wheel 92 will makeone complete revolution in forty minutes. in this manner, the speed ofcam can be changed by movement of the shift plate 34 and thereby changethe frequency of advance of the cam barrel assembly driven by theratchet wheel 92. However, the shift plate 34 must be locked inengagement since the reaction forces from the gear engagement, undersome circumstances, tend to drive the -shift plate 34 and the gearscarried thereby out of engagement with the drive pinion 26.

In order to maintain the shift plate 34 and the keeper plate 35 in theselected position, a mechanical interlock is embodied in the instanttimer. The position of the shift plate 34 and the keeper plate 35 iscontrolled by a lever 48 which is attached to a shaft 50 journalled inthe back plate 14. A torsion spring 52 has one end engaging an actuator53 attached to the shaft 50 and the other end engages an abutment 54 ona latch arm 56 which is journalled on the shaft 50. The latch arm 56engages an arm 58 formed on the shift plate 34. The shift plate 34 isalso formed with a projection 60 and a second arm 62. One end of atension spring 64 is attached to the arm 62, the other end of the spring64 being attached to a pin 66 secured to the back plate 14. The abutment60i is selectively engageable with diametrically opposed arcuateabutments 72 and 74 integral with the gear 44.

The arcuate abutments 72 and 74 coact with the abutment 60 on the shiftplate 34 to form an interlock for preventing pivotal movement of theshift plate 34 during advance of the ratchet wheel 92 thereby preventingdisengagement between the drive pinion 26 and either gear 30 or gear 68.As seen in FIGURE 4, the gear 44 drives a two-lobe cam 75 havinggradually sloped rise surfaces 76 and abrupt drop surfaces 78. The cam75 is engaged by a follower 80 which is pivoted on a bushing attached tothe back plate 14. The cam follower has one end of a tension spring 84attached thereto for maintaining the follower in engagement with the cam75. The other end of the tension spring 84 is attached to a pin 86carried by the back plate 14. In addition, the cam follower 80 has adrive pawl 88 connected thereto by a pin 90 and maintained in engagementwith the sixty toothed ratchet wheel 92 by a torsion spring 94. The pawl88 drives the ratchet wheel 92, the ratchet being keyed, or otherwisesuitably connected to the shaft 25. A stop pin 96 supported by the backplate 14 is employed to limit movement of the follower 80 in thecounterclockwise direction during movement of the cam follower 80 underthe urge of spring 84 as seen in FIGURE 4.

The cam 75, the cam follower 80 and the pawl 88 constitute a drivemechanism for imparting step by step movement to the ratchet wheel 92and the shaft 25 during rotation of the gear 44. The gear 44 is rotatedin the direction of arrow 98, and as the follower 80 engages the rise 76of cam 75, the follower 80 is pivoted in the clockwise direction aboutthe bushing supporting the same whereby the torsion spring 94 will movethe pawl 88 into engagement with a ratchet tooth. During continuedrotation of the cam 75, the follower will move down the sharp drop 78 ofthe cam 75 under the urge of spring 84 and thus impart a one toothmovement to the ratchet wheel 92.

With the shift plate 34 in the position shown in FIG- URES 2 and 4,projection 60 on the shift plate 34 is beneath either arcuate projection72 or arcuate projection 74 thereby preventing clockwise movement of theshift plate 34 when the follower 80 starts down the sharp drop 78 of thecam 75. In this manner, the coaction between projection 60 and lugs 72or 74 prevents disengagement between the drive pinion 26 and the pinion30 when the cam follower 80 attempts to drive the gear 44 faster thanthe pinion 26. On the other hand, when the shift plate 34 is in theposition depicted in FIGURE 3 wherein the pinion 26 engages the pinion68, the projection 60 is located above the arcuate abutments 72 and 74so that when the follower 80 begins its movement down the sharp drop 78of the cam '75, the projection 60 cooperates with the projection 72 orthe projection 74 to prevent counterclockwise movement of the shiftplate, thereby preventing disengagement between drive pinion 26 andpinion 68.

When lever 48 is rotated in the counterclockwise direction, as viewed inFIGURES 2 and 4, the actuator 53 rotates with the shaft 50 therebyloading torsion spring 52 so as to apply a counterclockwise torque tothe latch arm 56. The latch arm thereby applies clockwise torque to theshift plate 34. If the teeth of pinion 68 do not mesh with the teeth ofdrive pinion 26 when the shift is attempted, the spring 52 is extendedthereby providing torque on the latch arm 56 and the shift plate 34 torotate the shift plate 24 in the clockwise direction until the teeth ofthe pinion 26 mesh with the teeth on pinion 68. When the shift iscompleted, the latch arm S6 will move counterclockwise into engagementwith a stop pin carried by the back plate 14. In this position the endsurface 56a of the latch arm 56 rides on the surface 58a of the shiftplate arm 5S to form a mechanical lock for the shift plate 34. lf aspeed change is attempted when the cam follower 80 is approaching thesharp drop 78 on the cam 75, the coaction between the projection 60 onthe shift plate 34 and the end lug 72 or 74 will prevent shifting of theplate 34 until the advance of the ratchet wheel 92 is completed.

When the pinion 68 engages the drive pinion 26, the timer is driven athigh speed. In order to drive the timer at low speed, the lever 40 ismoved to the clockwise direction from the position of FIGURE 3 to theposition of FIGURES 2 and 4. As the lever 48 is rotated in the clockwisedirection, the actuator 53 imparts clockwise movement to the latch arm56 thereby releasing the shift plate 34 and permitting spring 64 torotate the shift plate 34 in the counterclockwise direction so as toengage pinion 30 with the drive pinion 26. This shift likewise cannot bemade when the cam follower is approaching the sharp drop 78 on the cam74 due to the interlocking action between the projection 60 and eitherarcuate projection 72 or 74. When the drive pinion 26 engages the pinion30, the timer is driven at low speed.

As seen particularly in FIGURE 2, the shaft 25 is formed with a keyway100 for receiving a key to drivingly connect a cam barrel assemblyincluding a cam 102 for rotation with the shaft 25. The cam 102constitutes a main motor cam having suitably programed rises and dwellson the periphery thereof including surface A, surface B and surface Cfor actuating a switch 106 comprising a movable contact 108, astationary contact 110 and 111 and a cam follower 104. The cam 102 isformed with an arcuate slot 112 subtending an angle of approximately 75.A constant fill cam 114 is journalled on a hub portion 116 of the cam102. 'Ihe constant ll cam 114 has a projection 118 extending through anarcuate slot 112 and a radially extending cam portion 120 for actuatingthe switch 106. The cam 114 has a second radially extending arm portion122 formed with ratchet teeth 124 on the same radius as the teeth ofratchet wheel 92. The drive pawl 88 is of sufficient width to engageboth ratchet wheel 92 and the ratchet teeth 124. The constant fill cam114 is normally biased so that end 118a of the projection 118 engagesend 112a of the arcuate slot 112 by means of a torsion spring 126. Oneend of the torsion spring 126 engages the projection 118 and the otherend engages an abutment 128 integral with the cam 102. The cam surfaceon the constant fill cam 114 is formed with an abrupt shoulder 130 whichis engaged by the cam follower 104, as seen in FIGURE 2, so as toprevent movement of the cam 114 when the cam 102 is manually turnedcounterclockwise. Under these conditions, the ratchet wheel 92 and thecam 102 will rotate in the counterclockwise direction, as viewed inFIGURE 2, relative to the constant ll cam 114 until end 118b theabutment 118 is engaged by end 11211 of slot 112 so as to disengage thecam follower 104 from the shoulder 130, thereby cancelling the fourminute ll time and the wash time.

The variable wash period is obtained through the displacement of the tab118 with respect to surfaces 112e and 1Mb of slot 112. The rst tooth ofthe ratchet segment integral with the fill cam engages the drive pawl S8as switch follower 164 is against abutment 130. As cam 162 is turnedcounterclockwise byV shaft 25, it will displace the tab 118 from slotend llZa reducing the wash period. When the desired wash time has beenselected the shaft 25 is axially pushed in starting the timer motorwhich in turn will actuate the lever titi moving pawl 8S to the nexttooth of the ratchet segment. This will continue until four minutes oftill time has elapsed at which time the segmented gear will no longerhave any tooth engagement with the pawl and the switch follower 104 willfall to the surface B on cam 102 starting the agitating cycle, alsoallowing cam 114 to reset itself so that tab 118 is again against end112a of the slot 112.

With reference to FIGURE 4, a disc 132 is attached to the gear 44, thedisc having a pair of diametrically opposed axially extendingprojections 134. The projections 13d coact with a lever 136 pivoted at13S to the back plate 14 and having a leg 140 adapted to be engaged bythe projections 134. The other end of the lever 136 carries a roller 142of insulating material adapted to engage a leaf spring 144 carrying amovable switch contact 146. The contact 146 is engageable with a fixedcontact 143. T .e switch comprising contacts 146 and 14S is periodicallyopened twice during each revolution of the gear Litt. The inherentresiliency of the leaf spring 144 maintains the leg Mtl in the path ofmovement of the projections 134 so that at all times when the leg 140does not engage a projection 134, the switch contacts 146 and 1458 aremaintained in the closed position.

As alluded to hereinbefore, the shaft 25 is both rotatable and axiallymovable. A knob 151B may be conveniently attached to the shaft 25 formanually imparting axial movement and rotation to the shaft. The shaft2S is formed with an annular groove 152 which receives a bi furcated endof a lever e. The other end of the lever 151i is received in a notch ofan insulating switch actuator 156 supported for pivotal movement by apin 158. The pin 158 is attached to the back plate 14. The actuator 156engages a leaf spring lett carrying a movable contact 162 engageablewith a fixed contact 164. The leaf spring 16d is inherently biased sothat the movable contact 1&2 engages the ixed Contact led. When theshaft 25 is moved axially to the left, as viewed in FIGURE 4, the lever154 imparts counterclockwise pivotal movement to the actuator 156 so asto disengage the contacts 162 and 16st. The switch contacts 162 and 164may conveniently be used as the control switch for the synchronous motor1d such that the synchronous motor 19 is energized only when the knob15) and the shaft 25 are moved axially to the right, as viewed in FIGURE4.

Operation of the two-speed timer is as follows: When the lever 4S is inthe position of either FIGURES 2 or 4, the timer operates on a slow, orsixty minute cycle. On the other hand, when the lever 4S is in theposition of FlGURE 3 the timer operates on a forty minute, or fastcycle. The lever 4S can be moved between its limit positions at any timeduring the cycle. However, when cam follower 8d starts down the sharpdrop surface 73 of the cam 75, a shift cannot occur due to theinteraction of tab titl and either tab '72 or tab 7d. The switchcomprising contacts 145 and 14? is `alternately opened and closed twiceduring each revolution of the gear Accordingly, on a sixty minute cyclewherein the gear 44 rotates thirty revolutions per hour, the switchcontacts 1de and 14S are opened every minute. On the other hand, whenthe timer is operating on a fast cycle wherein the gear li rotates at 45r.p.h., the switch contacts 146 and 14's are opened every for-tyseconds.

When the timer is operating on the sixty minute cycle, the ratchet wheel92 and the cam barrel assembly driven thereby rotates a distance of onetooth every sixty seconds. When the timer is operating on the fast cycleof forty minutes, the ratchet wheel 92 and the cam barrel assemblydriven thereby is rotated throughout a distance of one tooth every fortyseconds. The constant ll cam 114 coacts with the main motor cam 102 soas to assure a four minute fill period during the sixty minute cycle anda two and two-thirds minute period during the forty minute cycleirrespective of the Washing period selected by the operator. It is to beunderstood that the shaft 25 can be manually rotated to advance thetimer at any time to enable the operator to select the desired washinginterval. If a full ten minute washing interval on the sixty minutecycle is selected, the constant fill cam 114 is driven throughout adistance of four teeth by the pawl 3S through the ratchet tooth section124 with the main motor cam 102. if a washing interval of less than tenminutes is selected by the operator, the cam follower 104 engages theshoulder on the constant fill cam 114 during manual rotation of the cambarrel assembly so as to assure a four minute till period on the sixtyminute cycle. When the synchronous motor 1d is energized, the drive pawl33 will drive both the ratchet wheel 92 and the ratchet segment 12d todrive the constant lill cam 114 and the main cam 1&32. When the fourmin-nte till period has elapsed the ratchet segment 124 will bedisengaged from the pawl 8d thereby permitting the torsion spring 126 torotate the constant fill cam 114 so that the abutment 11 engages the end112e of the slot 112, and in so doing the till period is terminated.During the fast cycle of forty minutes, the constant fill period isreduced to a time interval of two and two-thirds minutes irrespective ofthe selected washing interval.

While the embodiment of the invention as herein disclosed constitutes apreferred form, it is to he understood that other forms might beadopted.

What is claimed is as follows:

l. An impulse timer including, a drive pinion, a driven gear operativelyengageable with said drive pinion, a ratchet wheel, a drive pawlmechanism actuated by said driven gear for imparting step by stepmovement to said ratchet wheel, a cam barrel assembly driven by saidratchet wheel including a main motor cam, a constant till cam journalledon said main motor cam and having a lost motion driving connectiontherewith, and means for driving said constant ll cam from said drivepawl mechanism to obtain a constant till period.

2. A two-speed impulse timer including, a drive pinion, a driven gear, adrive pawl mechanism actuated by said driven gear, a manually selectabletwo-speed transmission between said drive pinion and said driven gear,and 'uiterlock means preventing disengagement between the drive pinionand the transmission during advancing movement of the drive pawlmechanism.

3. A two-speed impulse timer including, a drive pinion, a driven gear, adrive pawl mechanism actuated by said driven gear, a manually selectabletwo-speed gear transmission between said drive pinion and said drivengear, a pivotally movable shift plate carrying said two-speed geartransmission, and coacting lug means on said shift plate and said drivengear for precluding disengagement of said two-speed gear transmissionand said drive pinion during advancing movement of said drive pawlmechanism.

4. A two-speed impulse timer including, a drive pinion, a driven gear, ashift plate carrying a two-speed gear assembly for establishing adriving connection between said drive pinion and said driven gear, adrive pawl mechanism actuated by said driven gear including a canihaving gradual rises and abrupt drops, and coacting lug means on saidshift plate and said gear for precluding disengagement of said geardrive assembly and said drive pinion during advancing movement of thedrive pawl mechanism.

5. The two-speed timer set forth in claim 4 wherein said cam is formedwith two rises and two abrupt drops, and wherein said gear is formedwith a pair of diametrically opposed lugs coacting with a single lug onsaid shift plate.

6. An impulse timer including, a drive pinion, a driven gear operativelyengageable with said drive pinion, a drive pawl mechanism actuated bysaid driven gear, a ratchet wheel driven by said escapement mechanism, acam barrel assembly driven by said ratchet wheel including a main motorcam, a constant fill cam journalled on said main motor cam and having alost motion driving connection therewith, said constant lill cam havinga ratchet tooth segment drivable by said drive pawl and an abutment, andcam follower means engageable with said abutment whereby said constantfill cam is driven by said drive pawl mechanism for assuring a constantll period.

7. The impulse timer set forth in claim 6 wherein said main motor camincludes an arcuate slot, said constant ill cam having a lug disposedwithin said slot, and torsion spring means biasing said constant fillcam for normally maintaining the lug in engagement with one end of saidslot.

References Cited in the file of this patent UNITED STATES PATENTS FoxAug. 21, Reynolds July 7, Kreitchman et al Feb. 12, Snoddy Nov. 3,Niemand Dec. 16, Sisson Ian. 27, Constantine May 31, Timon et a1. May16, Schneider May 23,

FOREIGN PATENTS Germany Dec. 15,

1. AN IMPULSE TIMER INCLUDING, A DRIVE PINION, A DRIVEN GEAR OPERATIVELYENGAGEABLE WITH SAID DRIVE PINION, A RATCHET WHEEL, A DRIVE PAWLMECHANISM ACTUATED BY SAID DRIVEN GEAR FOR IMPARTING STEP BY STEPMOVEMENT TO SAID RATCHET WHEEL, A CAM BARREL ASSEMBLY DRIVEN BY SAIDRATCHET WHEEL INCLUDING A MAIN MOTOR CAM, A CONSTANT FILL CAM JOURNALLEDON SAID MAIN MOTOR CAM AND HAVING A LOST MOTION DRIVING CONNECTIONTHEREWITH, AND MEANS FOR DRIVING SAID CONSTANT FILL CAM FROM SAID DRIVEPAWL MECHANISM TO OBTAIN A CONSTANT FILL PERIOD.